The present invention generally relates to a temperature control apparatus for an air-conditioning apparatus having cooling and heating modes of operation, which utilizes a microcomputer for maintaining a generally comfortable temperature at all times within a space to be air-conditioned.
In general, the temperature within a space to be air-conditioned, for example, a house room, (this temperature being hereinafter referred to as "indoor temperature") which is considered comfortable to most people, varies with a variation of the temperature outside the space to be air-conditioned, that is, the outdoor temperature. By way of example, when the outdoor temperature is 35.degree. C., 23.degree. C., or 20.degree. C., the indoor temperature of 27.degree. C., 23.degree. C., or 20.degree. C., respectively, is considered comfortable, and the indoor climatic condition acceptable to most people has heretofore been published by some experts concerned.
When operating an air-conditioning apparatus having cooling and heating modes of operation, (that is, an air-conditioning apparatus of the dual purpose type which can serve as a heat pump, the operator of the air-conditioning apparatus utilizes his sensory perception to determine whether the air-conditioning apparatus is to be operated in a heating mode or whether it is to be operated in a cooling mode. Moreover, whether the air-conditioning apparatus is operated in the heating mode or in the cooling mode, the user manipulates a temperature adjustment of the air-conditioner, in dependence upon a sensory perception of the temperature prevalent within the house room in which he or she lives, to central the air-conditioner so as to create an acceptable indoor climatic condition.
Since the temperature control used in most conventional air-conditioners of a similar kind operates on the basis of an absolute temperature control principle, the indoor climatic condition, particularly the indoor temperature, created by the dual purpose air-conditioner is determined by the setting of the temperature control irrespective of variation in outdoor temperature. This often results in excessive cooling or heating of the house room.
Not only does the excessive heating or cooling of the house room adversely affect physical conditions of some or all of occupants in the house room, but also it results in a waste of electric power in view of the fact that the air-conditioner is operated to provide energies in excess of the amount required to establish an acceptable indoor temperature.
The above described drawback would be substantially eliminated if the temperature at which the temperature control of the dual purpose air-conditioner operates is made variable according to a variation of the outdoor temperature. The arrangement necesssary to achieve this involves complications and, therefore, has not yet been practised in the control of air-conditioners.